Answer:
The correct option is 2.
Explanation:
In the given figure, there are 5 vertices and 5 edges.
In an efficient network, if we have n vertices, then (n-1) edges are required to connect all vertices.
Let the vertices are A, B, C, D and E.
The edges BC, CD, and DB form a cycle. If we remove any edge from these edges, then we have enough edges to connect all the vertices.
Therefore the statement "Given graph is an efficient network" is false. This network has a cycle making it inefficient and option 2 is correct.